Method of making phosphorus oxychloride



- ence of chlorine'gas. 1..1

v Patented Q Q I V V H 1.921.370 V I H r METHOD OF MAKINGPHOSPHORUS' 1 I -OXYCHLORIDE; H I Clayton 01in Nansen; wgva, assignor to KavalooTroduots,.Inc., Nitro, W. Ya, a Cor- ,poration of WostVirginia I T i I i .i No nrawiiig. Application anuary 12; 1933" serial -No.f651,368 I io'clerms. (o1. 23-'- 203) This invention relates to oiymaking isfa solid-and is exceedingly corrosive and hard phosphorus onychlorideq j i to handle. Also it is quitedifficult to make.

One object Of'llly invention-is the provision of a hiypreferredjmethod isto oxidize phosphorus method whereby phosphorus cxychloride. may .betrichloride by'adding chlorine thereto in the pres- V 5 made Without'theobjectionable features inherent' enceofan oxygen bearing compound. To accominfmethods previously used, l 1 1 plish this result Imix phosphorus trichloride, and

Another object of this inventionis the provision phosp o pentoxide in e pe proportionsof a method for making phosphorus oxychloride No reaction occurs until chlorine is passed in-.

byoxi'dizing phosphorus-trichloride in the pres Aftel' 't p p a y of chlorine has been --Other objects willjbe in part obvious and in part goes forwardasfollowsz i p v pointed out hereinafter. v I w Phosphorus oxychlorideiis awidely used reagent 1 Y B k39h C T' r for many organic condensation r ti nd The phosphorus trichloride is easily handled since 15" finds particular application in the; preparation of it is a liquid and the chlorine "can be fed in from triphenyl and tricresyl phosphatesboth'of which weighed cylinders so that thewhole operation areusedas plasticizers for celluloseacet ate, celunder-Very C 95 fll i 1 v lulose "nitrate a'ndfor various, resins. 'Tricresy1-- The following examples are v t'hflw phosphate'has also been proposed for use-in elset mBthOdmaYbB'CaTfiQQ out, but it isto be ex- '20' trical insulation, waterproofing of sheilac'andthe P 1 13 n e d h t I amn t restr ct d tothe like. e exact proportions and s ecified conditions. 7 Phosphorusfoxychloride is prepared'by. the-oxi- E- P N -'--T 11101136111941 {11133131111913} dation of phosphorus:trichloride (P013) The' old ,-4' .5pa tts yi w 1e"h.t-of p Ph H methodwhichiisstilliused by some manufacturers i 'l Were Placed In a p fi e 5 25 carries outithis oxidation by meansoissodium parts by Weight of phosphorus pentoxido were chlorate '(NaClO3). The reaction which takes d :T receptacle'was,provided:vlith a-stirplaceis as follqws; p rer; .ajchlorine inlet and areflux condenser; i Means forheating the receptacle Wasprovided. 3PC13+NaClQ3=3POCl3+NaCL The introduction of chlorine was begun and the This method gives a very nice grade of phosphorus rieceptacle slowly g g means of Water g g r 0 about 76? C. T e c orine was absorbe I y gil g ggi f g gygfi ifg gg gg g3 29 the mixture. During the reaction, the tempera- I In the first place the sodiumchloride produced z flY- z g' fi it by the reaction always hoids some'phosphorus wolr S 0 e Dipper 1 y 0 Q Dune oxychloride and since the sodium chloride must was added h refluxmg temperature W 3 be removed at stated intervals thereis a loss of 23 3 fi g fi ggi ggg g g fi ggg fi gfg the oxychloride. Also the sodium chloride cakes beramre was about C t amount ch10: readily and a POWerfHI stirrer is required to rine charge d was. 206 4 parts by Weight The .vent such caking. lhere is considerable abra- Weight of crude reaction mixture was about v sion and the apparatus does not last very long. 767

r parts by. weight. Thetlme of the reaction Furthermore, the removal of the sodium chloride was about 171 minutes. The crude reaction is a very unpleasant operaiion which b ture was then fractionated. The. first fraction, 7 formed by operators wearing gas masks, as phosboiling between 101 and was about 15 phorus oxychloride fumes produce intenselun parts by Weight Themain fraction-boiled and throat irritation.

It has been known for some time that'phospho rus pentachloride andphos'phorus pentoxide reg ggi z i g g z g pomt the mam act and yield phosphorus oxychloride according" Example No. charge of this example tween 106 and 107.5 (Land wasabout 626 parts 5 h following reactions: 7 contained 142 parts by weight of phosphorus P2O5+3PC15:5POC13 J pentoxide and 453.? parts by Weight of phosphorus trichloride. It will be noted that in these *This reaction goes very nicely but unfortunately proportions there is an excess of 10% of phos- U the main difliculty is in the preparation and hanp'horus trichloride. The chlorine charged in was l dling of phosphorus pentachloride. The material 1 about 198.4 parts by weight and the time. required added,- the reaction is completed.- Thisreaction 65 v for the reaction was about 172 minutes. The yield of crude material was about 807.5 parts by weight. The first fraction which boiled between 88 and 105 C. contained about 126.5 parts by 5 weight. The main fraction boiling between 105 and 108.5? C. was about 634 parts by weight. There was a small residue inthe reaction receptacle. Analysis of the first fraction showed it to be about 13.2% phosphorus trichloride and the balance phosphorus oxychloride.

One form of kettle or receptacle which may be used is a lead lined one having coils for heating or cooling the reaction mass. The kettle is also equipped with a reflux condenser and a stirrer. Another charge which may be used consists of about 726 parts by weight of phosphorus trichloride and about 250 parts by weight or" phosphorus pentoxide. The kettle is charged cold, and the lid is clamped on; The temperature is 0 raised to about 60 C. and is gradually increased to about 90? C. as the reaction proceeds. The mixture is stirred to insure uniform heating and thorough mixing. Chlorine is fed in from weighed cylinders, the usual quantity required is about 375 parts by weight. It takes about five hours to complete the reaction. When the reaction is over, which is indicated by the color of the refluxing liquid becoming yellow, the 7 charge is dropped into an enamelled still which is equipped with a column and reflux condenser,

and distillation is carried out in the usual. man'- ner, employing a still, column, reflux condenser and condenser. The excess phosphorus trichloride is first distilled off and then the phosphorus oxychloride is distilled. This gives a very high grade material containing a very small percentage of phosphorus trichloride. Ordinarily a yield of about 1350 parts by weight of hosphorus oxychloride is obtained from this charge. 40 While specific examples have been'above given, it is to'be expressly understood that variations of the proportions and conditions within limits are permissible and come within the scope of I the invention disclosed.

What I claim is: v 1.- A method of the character described, which comprises mixing phosphorus trichloride and phosphorus pentoxide and then introducing a gas containing chlorine.

2. A method of the character described, which comprises adding a chlorine gas to a mixture of phosphorus trichloride and phosphorus pentoxide. I v

3. A method of the character described, which comprises adding a chlorine gas to a mixture of phosphorus trichloride and phosphorus pen- 6. A method of the character described, which comprises, adding a chlorine containing gas to phosphorus trichloride and phosphorus pentoxide, raising the temperature of the mass while adding more chlorine containing gas until the reaction is complete.

'7. A methodof the character described, which comprises, reacting phosphorus trichloride, phosphorus pentoxide and chlorine to form phosphorus oxychloride, and then distilling to separate phosphorus oxychloride.

8. A method of the character described, which comprises, reacting phosphorus trichloride, phosphorus pentoxide and chlorine to form phosphorus oxychloride. a

9. A method of the character described, which comprises, adding chlorine to phosphorus trichloride and phosphorus pentoxide, addingmore chlorine and raising the temperature of the mass to approximately 100? C.

10. A method of the character described, which comprises, adding chlorine to phosphorus trichloride and phosphorus pentoxide, stirring the mixture, raising the temperature of the mixture while adding more chlorine. CLAYTON 'OLIN NORTH. 

